Effect of Flaxseed Gum on the Textural, Rheological, and Tribological Properties of Acid-Induced Soy Protein Isolate Gels

This study aimed to investigate the effects of incorporating different concentrations of flaxseed gum (FG) into acid-induced soy protein isolate (SPI) gels. The investigation focused on assessing the effects of FG on the textural, rheological, and tribological properties of the resultant SPI gels. The results showed that adding a small amount of FG (0.05%) to the SPI gel system increased the storage modulus (G′) and enhanced gelation while improving textural properties including hardness, viscosity, elasticity, and adhesion. Moreover, these gels exhibited strong water-holding capacity, a desirable property in various food products. However, when the concentration was increased to 0.3%, the WHC of the gel decreased, as did the hardness and cohesiveness. The particle size of the gel also increased with increasing concentration. Tribological investigations revealed that at 0.05–0.2% FG addition, the coefficient of friction (μ) of the composite gel was decreased compared to the pure SPI gel. In the sliding speed range of 1–100 mm/s, the coefficient of friction gradually increased with increasing concentration. When the FG concentration was 0.05%, the μ of the gel system was the lowest. In summary, low concentration of FG (0.05%) was found to play an important role in improving the properties of SPI gel, including enhancing textural, rheological, and lubricating properties.